DES MOINES, Iowa — The race for the Democratic presidential nomination moved into overdrive Saturday, as candidates scrambled to outdo each other to win over the Iowa activists who will leadoff the contest on Jan. 3.

Six Democratic rivals trotted out celebrities, filled the air with populist rhetoric and schmoozed party regulars in the most hectic day of a campaign that’s been intense for months.

The city took on a circus-like atmosphere as candidates raced from forums to rallies to marches to receptions, capped by the Iowa Democratic Party’s annual fundraising dinner. Nine thousand boisterous activists chanted and cheered during the event, which traditionally begins the sprint to Iowa’s leadoff caucuses in January.

Some of the hottest rhetoric of the night came from John Edwards, who has sounded an increasingly sharp populist theme in recent weeks.

“It is time for us as a party to stand up with some backbone and some strength for what we actually believe in,” said Edwards. “We do not believe in allowing lobbyists to write the laws of the United States of America and we do not believe that we are above the law.”

Edwards made a pointed reference to former President Bill Clinton and his failed effort to overhaul the nation’s health care system — an effort led by one of Edwards’ rival candidates, Hillary Rodham Clinton.

“It is not enough,” said Edwards. “Look at what happened in the 1990s when we had a Democratic president, a Democratic House and a Democratic Senate but still drug companies, insurance companies and their lobbyists killed universal health care in the United States of America.”

“I think it is time for us to give America hope,” said Edwards. “It is time to give those entrenched interests that are standing against America hell.”

Clinton-Obama matchup eyed closestBut it was the matchup between Clinton and Barack Obama that was watched closest.

Clinton has a significant lead nationally but only a small edge in Iowa, where she is being pressed by both Obama and Edwards. Clinton and Obama stacked the hall with larger contingents than their rivals, Obama bringing along a few thousand red-shirted backers and Clinton with an equal number of noisemaker-sporting supporters.

“When I am your nominee, my opponent won’t be able to say that I supported this war in Iraq, or that I gave George Bush the benefit of the doubt on Iran,” said Obama. “And he won’t be able to say that I wavered on something as fundamental as whether it’s OK for America to use torture — because it’s never OK.”

Obama has been critical of Clinton on all those issues, and he said Democrats are at their best “when we’ve led not by polls, but by principle, not by calculation but by conviction, when we’ve had leaders who could summon the entire nation to a common purpose — a higher purpose.”

“We are ready for change,” said Clinton. “Change is just a word if you don’t have the strength and experience to make it happen.”

Clinton argued the party should pick “a nominee who has been tested and elect a president who is ready to lead on day one. Fortunately, I have a little experience standing up and fighting for what I believe is right and what I believe America needs and how we can get there together.”

Clinton played the front-runner role to the hilt.

“I’m not interested in attacking my opponents,” said Clinton. “I’m interested in tackling the problems of America. We should be turning up the heat on the Republicans — they deserve all the heat we can give them.”

“The world is waiting for an American president they can trust,” said Joe Biden. “The American people are waiting for one of us to step up ... whom they can trust. Not trust in terms of our honesty, trust in terms of our judgment.”

Iraq at center of debateBill Richardson joined in the chorus of criticism over the war.

“The most important issue affecting this race is the war,” said Richardson, who hit his rivals on the issue.

“The leading candidates are talking about keeping troops (in Iraq) until 2013,” said Richardson. “I will bring troops home within one year and we will do it with a plan, a political compromise.”

At the same time, Richardson argued “it is critically important that Democrats not tear each other down” as the speeches wound deep into the night.

“Welcome to breakfast in Des Moines,” said Christopher Dodd, as he took the stage, saying major candidates have left open the potential that troops could be in Iraq until 2013.

“I’m not going to wait until 2013,” said Dodd. “Any Democrat who can’t stand up here and promise they’re gonna get our troops out of Iraq before 2013, I wonder what they’re standing for.”

Iowa Democratic Chairman Scott Brennan said the dinner traditionally marks a point where campaigns begin to get serious and voters begin deciding.

House Speaker Nancy Pelosi moderated the event, telling activists “they are going to hear from the next president of the United States.”

Advocates for various causes held news conferences seeking a slice of the heavy media attention. Anti-war activists were joined in a protest march by backers of former Sen. Mike Gravel and Ohio Rep. Dennis Kucinich, who were not invited to the dinner because they don’t have active campaign operations in the state.